In order to ensure normal teaching order, prote cting st ude nts ' healthy gr owth, e nsuring that national (property) is not lost, to preve nt or minimize t he occurrence of saf ety acci de nts, follow t he "prevent, re scue each other, e nsure safety and re duce losses" pri nci ple, a ccording t o the local con ditions, make the manag ement system. 1, t he pri ncipal is the re sponsibility of sc